This invention relates to a device for positioning a turntable of a desk-top cutting machine, and more particularly, to the positioning device of the cutting machine having a cutter mounted rotatably on to a base through a work support fence to be vertically swingable towards a workpiece to be cut disposed on the turntable.
One typical example of a desk-top cutting machine having a turntable positioning device of prior art is disclosed, for example, in Japanese Utility Model Laid-open (KOKAI) Publication No. 63-16921 (16921/1988) as briefly shown in FIGS. 8 and 9.
Referring to FIG. 8, a turntable positioning device of the prior art has a structure such that a steel ball 103 as an engaging member is inserted into a recessed portion 101 formed in a lower surface of a turntable 100 through a spring 102 also accommodated in the recessed portion 101. The steel ball 103 is urged against an upper surface of a base 104 by the urging force of the spring 102 and is engaged with a recessed portion 105 formed on an upper surface of the base 104. Otherwise, as shown in FIG. 9, the spring 102 and the steel ball 103 are accommodated in the recessed portion 101 formed in the base 104 and the steel ball 103 is also engaged with the recessed portion 105 formed on the lower surface of the turntable 100.
In the cases shown in FIGS. 8 and 9, when a workpiece mounted on the turntable 100 through a work support fence 106 is cut with a certain cutting angle, the turntable 100 is rotated. In a case where the work support fence 106 and a circular saw, not shown, are positioned with a suitable angle, the steel ball 103 comes into engagement with the recessed portion 105 formed on the base 104, thus angularly positioning the turntable of the cutting machine.
In such a state, when it is required to cut the workpiece with a certain angle, it is necessary to finely adjust the rotating position of the turntable 100. Namely, it is necessary to adjust either the work support fence 106 or the turntable positioning device.
However, in the prior art structure, the turntable positioning device is constructed as an integral structure with the turntable or base, so that it is difficult or impossible to adjust the positioning device itself. Accordingly, it is necessary to adjust the turntable positioning device by disposing or forming the work support fence independently of the turntable.
The independent formation of the turntable and the work support fence makes complicated the structure of the attaching portions thereof as well as the working thereof. Furthermore, there involves a problem of accidentally moving the work support fence during an actual working resulting in the degradation of a working performance.